Mystic River herring run is the largest in the state for 2024

More than 640,000 river herring passed through the fish ladder at the Mystic Lakes Dam in Medford in 2024, and around 37,500 herring made it into Horn Pond, according to the official estimate from the Massachusetts Division of Marine Fisheries (DMF). This year’s total at the Mystic Lakes was higher than any in the past five years, representing the highest population in the Mystic River watershed since 2019 and the largest river herring run in all of Massachusetts this year. River herring is a species of fish that lives in the ocean and returns to fresh water to spawn (lay their eggs). They are loyal to the lakes, ponds, and rivers where they were hatched and are an important part of oceanic and riverine food webs.

“That the most urbanized watershed in New England is also home to the largest river herring migration in the state is nothing short of remarkable,” said Senior Engagement Manager Daria Clark of the Mystic River Watershed Association (MyRWA). “This is thanks to sustained efforts by volunteers and MyRWA to protect water quality, expand access to habitat, and monitor this run size.”